Study shows why cockroaches are almost impossible to kill

A study published in the journal Nature Communications, called ‘The genomic and functional landscapes of developmental plasticity in the American cockroach,” found that cockroaches have a unique set of genes that gives them the capacity to thrive almost anywhere.

The several types of cockroaches used by the team from the South China Normal University had their essential building blocks drilled down. After the animal’s DNA was sequenced, the researchers observed that the American cockroaches, Periplaneta americana, have the second most significant known genome sequence of all insects.

These American cockroaches were found to be more genetically alike to some termite species than to other cockroach species.

Among other types, the DNA of the Australian cockroaches and smoky-brown cockroaches were sequenced as well. The team proceeded to compare them with already existing genetic informati0n from German cockroaches and termites.

The American Cockroach

Also called the ship cockroach, kakerlac, or waterbug, this species of insect is often considered a pest. Its origin dates back to the Carboniferous period, about 300 million years ago. It is mostly considered by the science community that its emerge occurred on the Pangea, or maybe in Gondwana. As it is a highly adaptative animal, it overcame the changes on Earth in those years, making it able to survive the massive extinction that other species did suffer.

The cockroaches’ DNA is vital to understand their complexity. Image credit: AP

Nevertheless, like many other species, the cockroach had to evolve to survive over the years, meaning its organism is a thoroughly modern developed one. This happened during the Quaternary period.

The cockroach is divided into three sections. The first part, the body, is a flat, broad oval, with a shield-shaped pronotum that covers its head. The second one is the pronotum, a plate-like structure which includes all or part of the dorsal surface of the thorax. The third and last section is the abdomen.

Besides a chewing mouth, long, segmented antennae, and leathery forewings with delicate hind wings, it also has a pair of large compound eyes, and each of them has over 2000 individual lenses. Compound eyes have reduced image resolution. However, the view angle is substantial, and they allow to have the capability to detect swift movement and the polarization of light.

The American cockroach is one of the fastest running insects. An experiment studied the record speed of one cockroach, and it reached 5.4 km/h (3.4 mph) – which translates into 50 body lengths per second. This was then estimated on human speed, which would represent a human being running at 330 km/h (201 mph).

Dissecting the cockroaches

The team found that the cockroaches had nearly as twice as many olfactory receptors (OR) as other insect species, making them have an incredible sense of smell. This, according to the study, represents a more accessible detection of traces of food, especially fermenting foods, which are the ones preferred by the Periplaneta americana.

The beginning of the American cockroach is dated to Pangea. Image credit: AP

The researchers explained that the examination showed that the American cockroach had over 500 gustatory receptors, which gives them the ability to withstand a more diverse diet, eventually helping the species to adapt.

The cockroaches adapted quickly as well when living in urban environments, considering the team found that the insects had several genes that allow them to face toxic environments. They also described how these cockroaches had more enzymes, making them capable of breaking down toxins and helping their immune stronger. In the research, the team explained:

“Our genomic and functional analyses in the American cockroach provided insights into its success in the adaptation to urban environments and the biology of developmental plasticity in cockroaches. Our study may shed light on both controlling and making use of this insect.”

So what does this all mean?

The final characteristic the team was able to found in the cockroach’s DNA was the genes that are responsible for re-growing broken limbs. The researchers amputated, systematically, the insects’ limbs and observed they were, in most cases, able to regrow. However, it also depended on the severity of the injury.

The researchers need further study to understand the animal. Image credit: Getty

This inspiring and hope-giving trait delighted the science community, as the found-DNA immediately started a process of healing and tissue regrowth – which later led the scientists to open a new path to further research, which will be studying how the cockroaches generate new tissue.

The team expects to discover the full potential of the healing properties of the cockroaches’ DNA, especially the “growth factor.” In the traditional Chinese medicine, these insects are ground up and use for several kinds of treatments because of this overwhelming regenerative power.

“We’ve uncovered the secret of why people call it ‘xiao qiang’. Now we want to know the secrets of Chinese medicine,” claimed the led author of the study, Sheng Li.